The primary objective ofthe Cancer Prevention (CP) program is to use population science research methods to improve the knowledge base for promoting overall reductions in cancer incidence, mortality and morbidity. The CP program has 21 members from 11 academic departments. This group of investigators accomplishes its goals through effective integration of expertise in Family & Preventive Medicine, Psychiatry, Communication, Computer Science and Engineering, Pediatrics, Psychology, Surgery, Endocrinology, Reproductive Medicine, and Public Health. The program is organized in 3 major scientific themes as follows. Theme 1 is Cancer-Related Policy Research; Theme 2 is Diet, Obesity, and Cancer Risk; Theme 3 is Physical Activity Assessment and Interventions. In 2012, the CP program had $10.2 million of peer reviewed research grant funding (direct costs), including $4.1 million from NCI. Members ofthe CP program published 554 programmatically aligned articles since 2007; 24% were the result of intra-programmatic collaborations and 20% were inter-programmatic. Significant scientific accomplishment include: (i) publication of the first report showing that nonsmoking policies have substantially reduced lung cancer rates in California and that this decline resulted from a decrease in the proportion of heavy smokers, (ii) the Women's Healthy Eating and Living (WHEL) study showed that maintenance of a low-fat diet high in vegetables, fruit, and fiber did not reduce recurrence or death in breast cancer survivors, and (iii) authorship of a landmark paper on built environment measures for physical activity. The program was active in 2012 with 1471 new patients in enrolled in intervention trials and 609 participants in observational studies. Proportions of participants by ethnic and racial categories approximate the MCC catchment area for adults aged 50 years and older (i.e., adults at risk of common-incidence cancers). The Cancer Center adds value to the research projects in CP by providing shared resource facilities, consultation on state of the art technologies, pilot project grants, opportunities for collaboration with other MCC programs, and recruitment of investigators.